A light-emitting device using a light-emitting diode (LED) is widely used for lighting devices such as a backlight of a liquid crystal display device, a signal apparatus, various kinds of switches, a lamp for a vehicle, and a general lighting. A white light-emitting LED lamp in which an LED and a phosphor are combined is focused as an alternative of an incandescent lamp, and development thereof is rapidly advanced. As a light bulb applying an LED lamp (hereinafter, noted as an LED light bulb), for example, one having an integral-type lamp structure is known. In the integral-type lamp, a globe is attached to a base part where a light bulb cap is provided, LED chips are disposed in the globe, further a lighting circuit of the LED chips is provided in the base part.
In a conventional LED light bulb, a combination of a blue light-emitting LED chip (blue LED) and a yellow phosphor (YAG phosphor and so on) emitting yellow light by absorbing blue light emitted from the blue LED is applied, and white light is obtained by a color mixture of the blue light emitted from the blue LED and the yellow light emitted from the yellow phosphor by absorbing the blue light. The LED light bulb in which the blue LED and the yellow phosphor are combined has characteristics in which brightness is easy to be secured. However, the white light based on the color mixture of the blue light from the blue LED and the yellow light from the yellow phosphor deteriorates in color rendering properties evaluated by an average color rendering index (Ra) and so on.
Light distribution of the conventional LED light bulb in which the blue LED and the yellow phosphor are combined is inclined toward a blue component and a yellow component, and light of a red component is insufficient. Therefore, reflected light when an object is seen by the light from the LED light bulb is different from natural light when it is seen under sunlight. In the conventional LED light bulb, the light emitted from the blue LED is used for generation of the white light, and therefore, luminance of a whole of the light bulb becomes uneven. Accordingly, it is difficult to reduce garishness and local dazzle of the light bulb, so-called glare. The blue light emitted from the blue LED strongly tends to go straight, and the light going in a horizontal direction goes straight as it is and is not scattered around, and therefore, it is difficult to make so-called a light distribution angle enough large.